Britain’s two biggest airlines said they remain optimistic that European travel markets will revive this summer even as vaccination campaigns stutter and plans to reopen borders are in limbo.

EasyJet Plc said Wednesday that while it will operate no more than 20% of 2019 capacity in the current quarter, it’s ready to ramp up flights from May given enough demand. British Airways said U.K. plans to resume travel are headed in the right direction and that Europe should follow suit in coming months.

There’s flexibility to rapidly boost operations and add destinations, EasyJet Chief Executive Officer Johan Lundgren said on a call, while cautioning that visibility over bookings is limited. The discounter lost as much as 730 million pounds ($1 billion) in the first half through March, according to a statement.

The airlines are talking up a travel rebound even as the likelihood of an imminent reopening remains uncertain. The U.K., their biggest market, has held back on confirming that citizens will be able to resume leisure travel from May 17, while the EU’s sluggish jabs program suffered a further blow when Johnson & Johnson delayed a vaccine rollout amid concern about side effects.

British Airways CEO Sean Doyle said he’s hopeful highly profitable trans-Atlantic flights will reopen soon and that the U.S. and U.K. have a chance to create a framework that could be copied by other countries. He predicted a revival in EU states as immunization gains traction, citing progress in Germany.

Shares of EasyJet traded up 3.1% at 952.20 pence as of 10:40 a.m. in London, extending gains so far in 2021 to 15%. BA owner IAG SA was priced 0.8% higher and is up 28% for the year.

Analyst Gloom

Many commentators are less optimistic than the CEOs about a summer revival.

John Grant, chief analyst at data specialist OAG, said airlines are on “shifting sands,” being forced to scrap 20% of flights at seven day’s notice and pushing back capacity increases planned for the next few weeks to August and beyond. Capacity is now likely to reach only 80 million scheduled seats a week by late September even in a best-case scenario, 20 million below estimates, he said.

Gerald Khoo, an analyst at Liberum, downgraded EasyJet to “hold” from “buy” Tuesday, citing an increasing risk that significant travel restrictions will remain. Khoo said previous forecasts assumed a rapid hike in capacity to 60% of 2019 levels in the June quarter. That’s three times what’s now planned.

Customer Confusion

What happens next in Europe remains an unanswered question despite recent government moves.

While Mediterranean sunspots are keen to admit vaccinated Britons, customers are being put off because the U.K. hasn’t yet said which destinations will see the fewest travel restrictions, Lundgren said. A requirement for everyone to undergo Covid tests is also acting as a brake, though should also mean “almost all major European countries” are on the so-called Green List, he contended.

Norwegian Air Shuttle ASA, which just emerged from insolvency proceedings, on Wednesday increased its fundraising goals to provide a stronger cash buffer amid uncertainty about the relaxing of travel rules.

EasyJet said its first-half results were “slightly better” than expected despite passenger numbers dropping 89%, with second-quarter cash burn lower than guided. The carrier has access to 2.9 billion pounds of liquidity as of March 31.

Lundgren said it’s not possible to provide further financial guidance given continued levels of short-term uncertainty. Final earnings figures for the six months will be published on May 20.